As he lies in a hospital bed in the video, Bowie sings: “Look up here, I’m in heaven. I’ve got scars that can’t be seen.”

According to The Guardian, Renck created the vision for “Lazarus” a week before learning of Bowie’s diagnosis.

“David said: ‘I just want to make it a simple performance video,’” Renck recalls. “I immediately said, ‘The song is called Lazarus, you should be in the bed.’ ... To me it had to do with the biblical aspect of it ... it had nothing to do with him being ill.”

Bowie kept his illness a secret from everyone but those closest to him, making his death a shock for fans.

“I don’t find it strange he kept his illness so private,” Francis Whately, who created the new documentary, told The Guardian.

“He’d had his life picked over for 40 years and he thought he had said everything he wanted to say, there was nothing more.”

Even some of the musicians who played on the “Blackstar” album didn’t know Bowie was sick, Whately said.

“I still don’t know if he started making Blackstar before he knew he was ill, or after,” said Whately.

“People are so desperate for Blackstar to be this parting gift that Bowie made for the world when he knew he was dying but I think it’s simplistic to think that. There is more ambiguity there than people want to acknowledge. I don’t think he knew he was going to die.

“However, he must have known there was a chance he wasn’t going to recover, so, to do an album with a certain amount of ambiguity in it, is Bowie playing the cat and mouse game that he always played.”